Hydraulically-operated diaphragm pump



July 1, 1930. B. STEVENS HYDRAULICALLY OPERATED DIAPHRAGM PUMP Filed DSG. 7, 1927 I/z yen/0f' Elem ey reif/e225.

l 4o that said Patented July l, 1930 PATENT oFFlcla IBLAIMEY STEVENS, OF TEMASGALTEEEC, MEXICO HYDRAULICALLY-OPERATED .'DIAPHRAGM PUMP Application led December 7, 1927. Serial No. 238,244.

This invention has to do generally with pumps, and is more particularly concerned with hydraulicallyJ operated diaphragm pumps wherein the actuating force is trans- 5 mitted to the diaphragm 'through a body of fluid, which I chose to term actuating fluid. The vibrations of the diaphragm, as .set up by the variable pressure of the actuating fluid, cause pulsations of the iuid to be pumped and, by the movement of suitable valves, cause the periodic ow of the last named Huid in a given direction.

Generally described, my pump includes a main chamber having inlet and outlet valves for the fluid to be pumped, a second chamber containing actuating Huid, a movable wall or diaphragm separatingthe two fluids, and means for varying the pressure of, or setting up pulsations in the actuat- 2'0 ing fluid.

An increase in actuating fluid pressure causes displacement of the diaphragm and a consequent displacementof a certain amount of main chamber fluid, the displaced fluid lifting the outlet valve and passing from the main chamber. At the same time, the increased pressure of the main-chamberfluid holds the inlet valve seated. Upon subsequent pressure drop in the actuating 3o Huid and the consequent return of the actuating luid body and diaphragm to their initial positions suction is created inthe main chamber, closing the outlet valve, opening the inlet valve, and' drawing a new Charge of fluid into said main chamber.

Water, oil or air may be utilized as the actuating iuid, though oil is preferably used, especially when a piston is employed for producing the iiuid pulsations, in order iston and its associated parts may be sel lubricated. Y

The means for producing pulsation of the actuating iiuid may beof any suitable character, for instance, I may utilize a plunger adapted to be reciprocated through the actuating fluid, and I have here shown such means, though this is not to be construed as limitative on the invention considered in its brader aspects. An understanding of the operation gained from this specific disclosure will lrender it equally understandable to those skilled in the art how the invention is applicable when other means are employed.

The semi-liquids and gases; or maybe 1n t e nature of an air or gas compressor. It may be utilized to exhaust air or gases from a given receptacle to produce a partial vacuum therein.

In United States Letters Patent No. 1,-v 627,257 issued to me May 3, 1927 and entitled Hydraulically operatedl diaphragm pump, I have disclosed a pump of the nature generally described above and have g5 there pointed out many f the outstanding advantages thereof. It will be unnecessary to repeat them here, for they apply equally well to the instant disclosure.

Now it is necessaryto continued efficient operation of this type of pump that the quantity of actuating fluid in the actuating v fluid chamber be kept substantially constant,

in spite of the fact that there are bound to be leakages therefrom. Otherwise, there is a gradual change in the mean position of the diaphragm or air is admitted to replace the lost fluid, with a coincident lowering of eiliciency, as will be readily understood..

In the aforesaid patent I have shown sev-v 8o eral means for replenishinv' theactuating Huid and for extracting air rom the actuating Huid chamber. -In the .present application I have .shown other means for accomplishing these results and it is to this feature that the present claims are drawn. The means here disclosed are such that the pump with its automatically acting replenishing means is reduced to utmost simplicity and yet acts with highest eiciency. However,

device is capable of pumping liquids, 55`

the means may be discussedto better advantage in connection with the following' detailed specification, reference being had to the accompanying drawings, in which the figure is a medial cross-section through a pump embodying my invention.

First, without regard to my improved means for replenishing the supply of actuating fluid, I will describe the general nature and operation of the pump.

A main or valve chamber 10 and secondary or actuating chamber 11 are defined by sections or housings 12 and 13, respectively, of pump casing 14. Housing 13 is in the nature of a dome secured to housing 12 by -bolts 11a.

A movable barrier or diaphragm 8 serves as a partition between chambers 10 and 11. Preferably, this diaphragm is marginally anchored, for instance, by being clamped between housings 12 and 13. This diaphragm may be of any suitable material (rubber, for instance) having the requisite quality of elasticity and preferably, resiliency. In its broader aspects, however, the invention includes the embodiment of a movable wall or separator plate entirely unattached to the side walls of the pump casing, though preferably (but not necessarily) in fluid tight engagement therewith.

In order to limit the extent of diaphragm movement, thus preventing said diaphragm from being over-stressed, I provide grids or perforated stop plates 9 and 9a above and below the diaphragm, respectively, both said plates being spaced from the diaphragm when the latter is unflexed. Preferably, the plates are of arcuate cross-section, as clearly illustrated,-in order that they may be substantially complementary to the diaphragm when the latter is flexed in either direction.

Pipes 15 and 1.6, respectively, lead to and from chamber 10, usual inlet valve 17 and outlet valve 18 serving as movable closuresK for pipes 15 and 16, respectively.

A piston or plunger `19vis adapted to be reciprocated through chamber 11 by any suitable mechanism, for instance, crank arrangement 20 which is adapted to be actuated fro'm any suitable power sourcel or prime mover (not shown). Piston 19 enters chamber 11 through a usual stuffing box 21.

Fluid B which is to be pumped (and which may be water, slime,'acid, etc.) normally fills chamber 10; while actuating fluid A, oil, for instance, completely fills chamber 11. When oil is used as the actuating fluid, it performs the additional' funetion of lubricating the piston and stuffing box. On the other hand, since diaphragm 8 holds fluid B from direct contact with thev piston and stufng box, the device is capable of pumping fluids which are destructive or detrimental to said piston and stuffing box.

In order more clearly to differentiate between the actuating fluid and the fluid tobe Ipumped, I will hereinafter refer to fluid A as oil and to fluid B as water, though these references to particular fluids are not to be considered as inferences that the pump does not function equally well to handle fluids having characteristics different from those named.

As before stated, and contemplated as being included within the scope of my claims, I may employ any suitable means for producing pulsations in or surges of fluid A, but I have chosen to illustrate reciprocatory piston 19 as a convenient and satisfactory pulsation producing means, and I will describe the operation of the device by referring to the mechanism shown, whereupon its operation in connection with other forms of pulsation producing means will be readily understandable.

Assuming piston 19 is at the limit of its 11p-stroke, that chamber 10 is filled by fluid B, and that chamber 11 is filled by fluid A, the downstroke of the piston causes displacement of fluid A and a consequent displacement or downwardly directed flexure of diaphragm 8. In its downward movement, the diaphragm 8 displaces a certain amount of fluid B, valve 18 lifting to allow the displaced water to pass into pipe 16.

Upon a subsequent up-stroke of the piston, oil A and diaphragm 8 return to their initial positions, tending to create a vacuum within chamber lO and hence closing valve 18 (the valve closing action may be aided by spring means, not shown, or gravity, if desired) opening valve 17 and admit-l ting or drawing a replenishing charge of water from pipe 15 into chamber 10. When diaphragm 8 is resilient as well as flexible, it aids in the return of fluid A to its initial position.

Thus, repeated pulsation or surges of fluid A bring 'about the alternate admission and expulsion of fluid B to and from chamber 10, the inlet and outlet valves serving to .direct'the flow in a given direction.

There is bound to be loss of fluid A lthrough stuffing box 21, and, if no compensating means were employed and the device were operated as a force pump, this loss of fluid would result in a gradual change in the mean position of the diaphragm, that is, said mean position would gradually approach grid 9. Under the same circumstances, if the device were operating as a suction pump, the oil lost through the stuffing box would be replaced by air entering through said box. Therefore, in the absence of compensating means, this loss of actuating fluid would cause a loss in pump elficiency'and finally render the pump inoperative. I have here shown a most simple and eiective means for overcoming this problem.

Assume rst that the level L of the source of supply or body B of the fluid tol be pumped is at given vertical distance from diaphragm 8, pipe 15 dipping into body B at a point below level L. .I then provide a reservoir R which contains a body C or replenishing source of supply of actuating iiuid, Vthe vertical distance of the reservoir from the pump having certain relationship with said given distance, as will be made apparent later. pipe 22, preferably jointless to eliminate all danger of leakage, extends from below the level L of body C to housing section 13 where it opens at 23 to chamber 11. A back-pressure valve 24, preferably, though not necessarily, immersed in the iuid within the reservoir, is provided in pipe 22 to prevent movement of fluid from said pipe back to reservoir R. It will be 4evident that both body B and body C are exposed to atmospheric pressure.

Now the relative effective heights of pipes 15 and 22 are such that during the suction stroke of the pump and with given fluids used the resultant effective pressure of the fluid to be pumped is greater than that of the replenishing supply of actuating fluid, the relative heights therefore de ending on the relative speciiic gravities of fluids B and C. Thus, during periods when replenishment of fluid within chamber 11 is unnecessary, on the upstroke of piston 19, it is assured that diaphragm 8 will rise to its mean position and that Huid B will flow into chamber 10, rather than actuating Huid from reservoirfR rising through pipe 22 and entering chamber 11 to hold the diaphragm down. If the actuating fluid in reservoir R. be of less specific gravity than that of the iiuid to be pumped (as is true in the illustrative case made here where the actuating Huid is oil and the uid to be pumped is water) level L must be lower than level L, the exact differential in height or hydrostatic head varying with the individual characteristics -of the particular fluids, factors of resistance, etc., but always being suiicient to insure proper action. Of course, where the actuating fluid is of greater specic gravity than the fluid to be pumped, level L may be above level L.

Now assume that there be escape of oil through stuliing box. Diaphragm 8 is then drawn against grid 9 during the upstroke of the piston and before said piston completes said stroke. The continued upward movement` of the piston to the end of its stroke tends to create a vacuum within chamber 11 and results in the iow under atmospheric pressure of replenishing iuid from reservoir R through pipe 22 into chamber 11, theprior leakage fromsaid chamber thus being automatically compensated and the normal efficiency of the pump continuing unimpaired.

It will-be recognized that in the pump the eifective intake pressure of the fluid to be pumped is substantially the same as. the pressure of the actuating fluid during the intake stroke. Hence the compensating means may be considered as a iuid supply connected with the actuating chamber 11 at an effective pressure less than the pressure of the actuating fluid during the intake of the fluid to be pumped.

In order to prevent the flow of air through the stuiiing box to chamber 11, I prefer to provide a Huid seal thereabout. This may conveniently be done by forming a cup-like flange 25 at the upper end of housing section 13 around stufling box 21. This cup is kept filled with iuid S at all times, the actuating fluid (usually oil) leaking through'the stuffing box tending to preserve a suiiicient quantity therein, once it has been initially filled. The operator is thus being relieved of this refilling duty.

In order that the actuating fluid may not be wasted and so reservoir R need not often be refilled, a drain tube 26 may lead from the cup, at a point above the stuffing box7 to reservoir R. The actuating fluid may thus be used over and over again, passing through the following cycle: reservoir R, pipe v22, chamber 11, stuling box 21, cup 25, drain 26 and reservoir R.

It will be understood the drawings and description are to be considered merely as illustrative of and not restrictive on the broader claims appended hereto, for various changes in design, structure and arrangement may be made without departing from the spirit and scope of said claims.

I claim:

1. In a pump, a casing defining two y chambers, a movable barrier between the chambers, a body of actuating fluid in one of the chambers, inlet and outlet valves adapted to control the passage of the fluid to be pumped into and out of the other chamber, means for producing pulsation in said actuating fluid in a manner to reciprocate said barrier, and means for replenishing the supply of actuating iuid to compensate leakage losses thereof, said lastmentioned means comprising a fluid supply connected with said one chamber and having an effective pressure less than the pressure of the actuating fluid during the intake of the iiuid to be pumped.

2. In a pump, a casing dening two chambers, amovable barrier between the chambers, a body of actuating fluid in one of the chambers, inlet and outlet valves adapted to control the passage of the fluid to be pumped Vinto and out of the other chamber,

said one chamber toward and away from the barrier to produce pulsation in said actuating uid in a manner to reciprocate said barner, means for replenishing the supply 5 of actuating Huid to compensate leakage losses thereof, said last-mentioned means comprising a fluid supply connected with said one chamber and having an effective pressure less than the pressure of the actuating Huid during movement of the plunger away from said barrier. 4 In witness that I claim the foregoing I have hereunto subscribed my name this 23rd day of November, 1927. BLAMEY STEVENS. 

